Hello

To start your preparation for the NEET exam, firstly, you should check the detailed syllabus and the exam pattern.
Formulate a study plan for your preparation and make a time table. You will have to manage your time for class 12th boards and NEET exam. NEET preparation is also based on the syllabus of NCERT textbooks only.
Your basic concepts of class 11 and 12 should be clear. Rote learning is not necessary, understanding of concepts is essential to clear the exam.
Apart from NCERT, you can also refer to other important books for in depth knowledge.
You can make short study notes and use it at the time of revision. Revision is also very important. After completing any topic/unit, you must revise it thoroughly.
Practice previous year question paper and mock tests.

All The Best!